Can old-time music lower your blood pressure? Probably not over the long term, but the paper is worth a listen. It's not the most rigorous study, and there are too many confounders, but any excuse to take in some Mozart or Strauss is welcome. They can keep the ABBA.
In an experiment, Ruhr University Bochum scholars enrolled 120 people and assigned them to either a music or control group (the latter just sat there), to see what happened to their blood pressure and other cardiovascular parameters with different types of music. In the music group, one third each got ABBA, Strauss or Mozart for ~25 minutes. Their systolic and diastolic numbers were recorded, along with serum cortisol levels and heart rate.
Regardless of music preferences, those listening to Strauss and Mozart saw a drop in blood pressure. This was across genders and ages.
So why not go all Dr. Oz and declare music a Miracle Vegetable? The problems are obvious; serum cortisol levels dropped for everyone, heart rates dropped for everyone, the musical styles for the two are different and the authors note one symphony (Mozart’s Symphony No. 40 in g minor) had the strongest effect. That's not really possible to declare validity, especially with such a tiny sample. That ABBA had lyrics so that led to less beneficial effect is just speculation on their part.
Really, exercise will do you more good than listening to music no matter how large the sample is. Our average life expectancy is 40 years greater than when everyone listened to Mozart, so Classical music wasn't better for health then any more than organic food was.
You probably want to ask why I listed Haydn in the title, when the experiment was about Mozart and others? Haydn was Mozart before Mozart was Mozart, just without any of the crazy -- and therefore no movie about him -- but he was so famous his head was stolen after he was buried. And Strauss was Romantic, not Classical. I can't endorse that. Also, I couldn't use something crazy like the neo-classical Stravinsky, because he makes Dr. Josh Bloom's ears bleed.
Really, if you believe that relaxing and enjoying some music will cause your health to improve, there is a 29 percent chance it might, so give it a try instead of watching television. Just don't use Haydn's Symphony No. 94, his "Surprise" Symphony. I bet that raises blood pressure rather than lowers it.
Citation: Trappe H-J, Voit G: The cardiovascular effect of musical genres—a randomized controlled study on the effect of compositions by W. A. Mozart, J. Strauss, and ABBA. Dtsch Arztebl Int 2016; 113: 347–52. DOI: 10.3238/arztebl.2016.0347